The conventional ultrasound imaging (sonography) uses high-frequency sound waves to view soft tissues such as muscles and internal organs. Because ultrasound images are captured in real-time, they can show movement of the body's internal organs as well as blood flowing through blood vessels.
In an ultrasound exam, a hand-held transducer is placed against the skin. The transducer sends out high frequency sound waves that reflect off of body structures. The returning sound waves, or echoes, are displayed as an image on a monitor. The image is based on the frequency and strength (amplitude) of the sound signal and the time it takes to return from the patient to the transducer. Unlike with an x-ray, there is no ionizing radiation exposure with this test
The conventional ultrasound imaging is used in many types of examinations and procedures. Some examples include: (a) Doppler ultrasound (to visualize blood flow through a blood vessel); (b) Bone sonography (to diagnose osteoporosis); (c) Echocardiogram (to view the heart); (d) Fetal ultrasound (to view the fetus in pregnancy); (e) Ultrasound-guided biopsies; (g) Doppler fetal heart rate monitors (to listen to the fetal heart beat).
The conventional ultrasound imaging has been used for over 20 years and has an excellent safety record. It is non-ionizing radiation, so it does not have the same risks as x-rays or other types of ionizing radiation.
The conventional ultrasound imaging is based on piezoelectric effect. A transducer is a very important part of the ultrasonic instrumentation system. The transducer incorporates a piezoelectric element, which converts electrical signals into mechanical vibrations (transmit mode) and mechanical vibrations into electrical signals (receive mode).
The conventional ultrasound imaging employs different frequencies. Lower frequencies between (0.5 MHz-2.25 MHz) provide greater energy and penetration in a material, while high frequency crystals that generate ultrasound in the range of (15.0 MHz-25.0 MHz) provide reduced penetration but greater sensitivity to small discontinuities.
High frequency transducers, when used with the proper instrumentation, can improve flaw resolution and thickness measurement capabilities dramatically. Broadband transducers with frequencies up to 150 MHz are commercially available.
There are also new medical procedures using High-Intensity Focused Ultrasound. High-Intensity Focused Ultrasound (HIFU, or sometimes FUS) is a highly precise medical procedure that applies high-intensity focused sonic energy to locally heat and destroy diseased or damaged tissue through ablation.
HIFU is also one modality of therapeutic ultrasound, involving minimally invasive or non-invasive methods to direct acoustic energy into the body. In addition to HIFU, other modalities include ultrasound-assisted drug delivery, ultrasound hemostasis, ultrasound lithotripsy, and ultrasound-assisted thrombolysis.
Clinical HIFU procedures are typically performed in conjunction with an imaging procedure to enable treatment planning and targeting before applying a therapeutic or ablative levels of ultrasound energy. When Magnetic resonance imaging (MRI) is used for guidance, the technique is sometimes called Magnetic Resonance-guided Focused Ultrasound, often shortened to MRgHIFU or MRgFUS. When diagnostic sonography is used, the technique is sometimes called Ultrasound-guided Focused Ultrasound (USgHIFU or USgFUS).
Currently, MRgHIFU is an approved therapeutic procedure to treat uterine fibroids in Asia, Australia, Canada, Europe, Israel and the United States. USgHIFU is approved for use in Bulgaria, China, Hong Kong, Italy, Japan, Korea, Malaysia, Mexico, Russia, Romania, Spain and the United Kingdom. Research for other indications is actively underway, including clinical trials evaluating the effectiveness of HIFU for the treatment of cancers of the brain, breast, liver, bone, and prostate.
In the present patent application, we propose a new technique to generate ultra-sound having ultra-high frequency up to GHz. This ultra-sound frequency is at least an order of magnitude higher that the max sound frequency achieved so far.
The proposed technique has the potential to create a new field of ultra-high frequency ultra sound imaging and treatment.